Platform rocking-chair



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'J. BEIERSDORP & W. I. BUNKER.

PLATFORM ROCKING CHAIR. No. 247,472. Patented Sept. 27,1881.

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UNITED STATES PATENT @FFICE.

JACOB BEIERSDORF AND WILLIAM I. BUNKER, OF CHICAGO, ILLINOIS.

PLATFORM ROCKING-CHAIR.

SPECIFICATION forming part of Letters Patent No. 247,472, dated September 27, 1881. Application filed November 15, 1880. (No model.)

lowing is a specification.

It is the object of our invention to produce a spring-connection for platform rockin g-chairs.

which willmake it unnecessary to use rigid stops, guides, or links of any kind, will hold the chair firmly down upon the base or platform, will draw the chair into position when twisted out of place, will not offer an absolutely rigid resistance to any movement of the chair on the base, will not suddenly arrest the rocking movement, will be cheap and simple in construction and durable in use. This we accomplish by using two broad stiff spiral springs oppositely coiled, and of greater diameter than length, and made of large closelycoiled wire, which springs have their end coils rigidly connected to brackets provided with flanges, by which the brackets are secured to the rockers and to the base. The springs are stretched somewhat when put upon the chair, so as to draw the chair positively and firmly down upon the platform. These springs are so broad thatin the ordinary rocking of the chair upon the base the movement of the springs is almost wholly a deflective movement, as contradistinguished from an extension of the springs.

It is well known that spiral springs can be much more easily deflected than extended.

()ur invention therein consists in the peculiar novel combination of devices employed by us, as fully hereinafter explained, and pointed out by the claim.

In the accompanying drawings, forming a part hereof, Figure 1 is an elevation of the inside of one rocker and the side rail of the base or platform upon which it rests, the parts being connected. by our improved spring-connection; Fig. 2, a cross-section through the rockers and platform of the chair on line 2 2 in Fig. 1, showing the right and left spring-connections in elevation Fig. 3, an elevation of the spring-connection in position, illustrating the principle of operation of our improved device.

Like letters denote corresponding parts in all the figures.

A A represent the side rails of the platform or base, and B B the rockers of the chair, such rockers resting directly upon said side rails.

G O arelarge spiral springs, each of which having flanges or arms a, by which said brackets are secured in position to the base rails and rockers of the chair. One of the springs, C, of each chair is a right-hand spiral, while the other spring, 0, is a left-hand spiral, as shown in Fig. 2. The purpose of this construction is to counteract the twisting or uncoiling tendency of the springs each by the other. If two right-hand springs are used, when the springs are extended in rocking, the twisting or uncoiling action of the springs in the same direction will displace the rockers somewhat on the platform. Each spring is a broad heavy spiral spring, closely coiled, and of greater diameter than length, the diameter of the spring being about two and a half inches and the length about two inches. It is made preferably of N0. 5 wire.

The preferred form of the brackets D D is shown in Figs. 1 to 3, inclusive. Each bracket is in the form of a semicircle, (or a smaller part of a circle,) I), from the ends of which the screw arms or flanges a project. This semicircle has a rib, 0, cast on its innerlower edge, upon which the end coil of the spring rests. At its center the semicircle b has a lug, d, on its upper side, which projects inwardly over the center of the rib c. A stove-bolt, c, is passed through this lug, and has a nut, e, on its inner end, and a washer, f between such nut and the lug. The bracket is forced against the end coil of the spring, the rib c entering between such end coil and the next coil of the spring. The washer f is then placed on the bolt 6, and the nut c is turned onto the same, forcing the washer against the inner side of .the end coil, and rigidly clamping it in the semicircle 1) between the rib c and lug d. The spring-seat in the semicircle is made on the curve of a smaller circle than the coil of the spring, so that such coil will bear solidly against the ends of the seat, and can be clamped rigidly to the bracket.

In securing the brackets to the rockers and base-rails thesprin gs are stretched somewhat, so as to separate the coils, as shown in Figs. 1, 2, and 3. This makes the springs act positively to draw the base and rockers together. It also is rigidly secured at its ends to brackets D D,

prevents the coils from rubbing together and making a noise wheh the chair is rocked. In the deflective movement of the springs the coils separate on one side and come almost, though not quite, in contact on the otherside, as shown in full lines in Fig. 3, while when the springs are extended the coils separate on both sides, though more on one than on the other, as shown in dotted linesin the same figure. The springs are so broad that in the ordinary rocking movement of the chair the point of contact between the rockers and the base does not extend much beyond the point x on either side, and consequently, as before explained, the springs have almost wholly a deflective movement. If the point of contact travels much beyond the point x-say to oc-the springs will be extended as wellas deflected, and the strength ofthe springs will stop the further movement of the chair by their combined defiective and end resistance. This double action of the springs makes the ordinary rocking movement of the chair very easy, while a yielding resistance is provided to keep the rocking movement within safe limits.

The chair, it will be seen, is not provided with any guides or stops, butis controlled and drawn back to a correct central position on the platform wholly by the action of the springs themselves.

What we claim as our invention is- In a platform rockin g-chair, the combination, with thebase-rails A A and rockersBB, resting upon such base-rails, of the broad and stifi' spiral springs G 0, connected rigidly with such base-rails and rockers, and being both deflected and extended when the chair is rocked, such springs being oppositely coiled and controlling wholly the movement and position of the rockers on the base-rails, substantially as described and shown.

JACOB BEIERSDORF. WM. I. BUNKER.

Vitnesses:

F. W. KASEHAGEN, O. W. MARBLE. 

